[llvm-commits] [llvm] r53203 - in /llvm/trunk: test/CodeGen/PowerPC/LargeAbsoluteAddr.ll utils/TableGen/DAGISelEmitter.cpp

Dan Gohman gohman at apple.com
Mon Jul 7 14:00:17 PDT 2008


Author: djg
Date: Mon Jul  7 16:00:17 2008
New Revision: 53203

URL: http://llvm.org/viewvc/llvm-project?rev=53203&view=rev
Log:
Refactor the tablegen DAGISelEmitter code for outputing calls to
getTargetNode and SelectNodeTo to reduce duplication, and to
make some of the getTargetNode code available to SelectNodeTo.
Use SelectNodeTo instead of getTargetNode in several new
interesting cases, as it mutates nodes in place instead of
creating new ones.

This triggers some scheduling behavior differences due to nodes
being presented to the scheduler in a different order. Some of the
arbitrary scheduling decisions it makes are now arbitrarily made
differently. This is visible in CodeGen/PowerPC/LargeAbsoluteAddr.ll,
where a trivial scheduling difference led to a trivial register
allocation difference.

Modified:
    llvm/trunk/test/CodeGen/PowerPC/LargeAbsoluteAddr.ll
    llvm/trunk/utils/TableGen/DAGISelEmitter.cpp

Modified: llvm/trunk/test/CodeGen/PowerPC/LargeAbsoluteAddr.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/PowerPC/LargeAbsoluteAddr.ll?rev=53203&r1=53202&r2=53203&view=diff

==============================================================================
--- llvm/trunk/test/CodeGen/PowerPC/LargeAbsoluteAddr.ll (original)
+++ llvm/trunk/test/CodeGen/PowerPC/LargeAbsoluteAddr.ll Mon Jul  7 16:00:17 2008
@@ -1,7 +1,7 @@
 ; RUN: llvm-as < %s | llc -march=ppc32 -mtriple=powerpc-apple-darwin | \
-; RUN:   grep {stw r3, 32751}
+; RUN:   grep {stw r2, 32751}
 ; RUN: llvm-as < %s | llc -march=ppc64 -mtriple=powerpc-apple-darwin | \
-; RUN:   grep {stw r3, 32751}
+; RUN:   grep {stw r2, 32751}
 ; RUN: llvm-as < %s | llc -march=ppc64 -mtriple=powerpc-apple-darwin | \
 ; RUN:   grep {std r2, 9024}
 

Modified: llvm/trunk/utils/TableGen/DAGISelEmitter.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/utils/TableGen/DAGISelEmitter.cpp?rev=53203&r1=53202&r2=53203&view=diff

==============================================================================
--- llvm/trunk/utils/TableGen/DAGISelEmitter.cpp (original)
+++ llvm/trunk/utils/TableGen/DAGISelEmitter.cpp Mon Jul  7 16:00:17 2008
@@ -18,6 +18,7 @@
 #include "llvm/Support/MathExtras.h"
 #include "llvm/Support/Streams.h"
 #include <algorithm>
+#include <deque>
 using namespace llvm;
 
 //===----------------------------------------------------------------------===//
@@ -1033,229 +1034,235 @@
       }
 
       unsigned ResNo = TmpNo++;
-      if (!isRoot || InputHasChain || NodeHasChain || NodeHasOutFlag ||
-          NodeHasOptInFlag || HasImpResults) {
-        std::string Code;
-        std::string Code2;
-        std::string NodeName;
-        if (!isRoot) {
-          NodeName = "Tmp" + utostr(ResNo);
-          Code2 = "SDOperand " + NodeName + "(";
-        } else {
-          NodeName = "ResNode";
-          if (!ResNodeDecled) {
-            Code2 = "SDNode *" + NodeName + " = ";
-            ResNodeDecled = true;
-          } else
-            Code2 = NodeName + " = ";
-        }
-
-        Code += "CurDAG->getTargetNode(Opc" + utostr(OpcNo);
-        unsigned OpsNo = OpcNo;
-        emitOpcode(II.Namespace + "::" + II.TheDef->getName());
-
-        // Output order: results, chain, flags
-        // Result types.
-        if (NumResults > 0 && N->getTypeNum(0) != MVT::isVoid) {
-          Code += ", VT" + utostr(VTNo);
-          emitVT(getEnumName(N->getTypeNum(0)));
-        }
-        // Add types for implicit results in physical registers, scheduler will
-        // care of adding copyfromreg nodes.
-        for (unsigned i = 0; i < NumDstRegs; i++) {
-          Record *RR = DstRegs[i];
-          if (RR->isSubClassOf("Register")) {
-            MVT::SimpleValueType RVT = getRegisterValueType(RR, CGT);
-            Code += ", " + getEnumName(RVT);
-          }
-        }
-        if (NodeHasChain)
-          Code += ", MVT::Other";
-        if (NodeHasOutFlag)
-          Code += ", MVT::Flag";
 
-        // Inputs.
-        if (IsVariadic) {
-          for (unsigned i = 0, e = AllOps.size(); i != e; ++i)
-            emitCode("Ops" + utostr(OpsNo) + ".push_back(" + AllOps[i] + ");");
-          AllOps.clear();
-
-          // Figure out whether any operands at the end of the op list are not
-          // part of the variable section.
-          std::string EndAdjust;
-          if (NodeHasInFlag || HasImpInputs)
-            EndAdjust = "-1";  // Always has one flag.
-          else if (NodeHasOptInFlag)
-            EndAdjust = "-(HasInFlag?1:0)"; // May have a flag.
+      unsigned OpsNo = OpcNo;
+      std::string CodePrefix;
+      bool ChainAssignmentNeeded = NodeHasChain && !isRoot;
+      std::deque<std::string> After;
+      std::string NodeName;
+      if (!isRoot) {
+        NodeName = "Tmp" + utostr(ResNo);
+        CodePrefix = "SDOperand " + NodeName + "(";
+      } else {
+        NodeName = "ResNode";
+        if (!ResNodeDecled) {
+          CodePrefix = "SDNode *" + NodeName + " = ";
+          ResNodeDecled = true;
+        } else
+          CodePrefix = NodeName + " = ";
+      }
 
-          emitCode("for (unsigned i = NumInputRootOps + " + utostr(NodeHasChain) +
-                   ", e = N.getNumOperands()" + EndAdjust + "; i != e; ++i) {");
+      std::string Code = "Opc" + utostr(OpcNo);
 
-          emitCode("  AddToISelQueue(N.getOperand(i));");
-          emitCode("  Ops" + utostr(OpsNo) + ".push_back(N.getOperand(i));");
-          emitCode("}");
-        }
+      emitOpcode(II.Namespace + "::" + II.TheDef->getName());
 
-        // Generate MemOperandSDNodes nodes for each memory accesses covered by 
-        // this pattern.
-        if (II.isSimpleLoad | II.mayLoad | II.mayStore) {
-          std::vector<std::string>::const_iterator mi, mie;
-          for (mi = LSI.begin(), mie = LSI.end(); mi != mie; ++mi) {
-            emitCode("SDOperand LSI_" + *mi + " = "
-                     "CurDAG->getMemOperand(cast<MemSDNode>(" +
-                     *mi + ")->getMemOperand());");
-            if (IsVariadic)
-              emitCode("Ops" + utostr(OpsNo) + ".push_back(LSI_" + *mi + ");");
-            else
-              AllOps.push_back("LSI_" + *mi);
-          }
+      // Output order: results, chain, flags
+      // Result types.
+      if (NumResults > 0 && N->getTypeNum(0) != MVT::isVoid) {
+        Code += ", VT" + utostr(VTNo);
+        emitVT(getEnumName(N->getTypeNum(0)));
+      }
+      // Add types for implicit results in physical registers, scheduler will
+      // care of adding copyfromreg nodes.
+      for (unsigned i = 0; i < NumDstRegs; i++) {
+        Record *RR = DstRegs[i];
+        if (RR->isSubClassOf("Register")) {
+          MVT::SimpleValueType RVT = getRegisterValueType(RR, CGT);
+          Code += ", " + getEnumName(RVT);
         }
-
-        if (NodeHasChain) {
+      }
+      if (NodeHasChain)
+        Code += ", MVT::Other";
+      if (NodeHasOutFlag)
+        Code += ", MVT::Flag";
+
+      // Inputs.
+      if (IsVariadic) {
+        for (unsigned i = 0, e = AllOps.size(); i != e; ++i)
+          emitCode("Ops" + utostr(OpsNo) + ".push_back(" + AllOps[i] + ");");
+        AllOps.clear();
+
+        // Figure out whether any operands at the end of the op list are not
+        // part of the variable section.
+        std::string EndAdjust;
+        if (NodeHasInFlag || HasImpInputs)
+          EndAdjust = "-1";  // Always has one flag.
+        else if (NodeHasOptInFlag)
+          EndAdjust = "-(HasInFlag?1:0)"; // May have a flag.
+
+        emitCode("for (unsigned i = NumInputRootOps + " + utostr(NodeHasChain) +
+                 ", e = N.getNumOperands()" + EndAdjust + "; i != e; ++i) {");
+
+        emitCode("  AddToISelQueue(N.getOperand(i));");
+        emitCode("  Ops" + utostr(OpsNo) + ".push_back(N.getOperand(i));");
+        emitCode("}");
+      }
+
+      // Generate MemOperandSDNodes nodes for each memory accesses covered by 
+      // this pattern.
+      if (II.isSimpleLoad | II.mayLoad | II.mayStore) {
+        std::vector<std::string>::const_iterator mi, mie;
+        for (mi = LSI.begin(), mie = LSI.end(); mi != mie; ++mi) {
+          emitCode("SDOperand LSI_" + *mi + " = "
+                   "CurDAG->getMemOperand(cast<MemSDNode>(" +
+                   *mi + ")->getMemOperand());");
           if (IsVariadic)
-            emitCode("Ops" + utostr(OpsNo) + ".push_back(" + ChainName + ");");
+            emitCode("Ops" + utostr(OpsNo) + ".push_back(LSI_" + *mi + ");");
           else
-            AllOps.push_back(ChainName);
+            AllOps.push_back("LSI_" + *mi);
         }
+      }
 
-        if (IsVariadic) {
-          if (NodeHasInFlag || HasImpInputs)
-            emitCode("Ops" + utostr(OpsNo) + ".push_back(InFlag);");
-          else if (NodeHasOptInFlag) {
-            emitCode("if (HasInFlag)");
-            emitCode("  Ops" + utostr(OpsNo) + ".push_back(InFlag);");
-          }
-          Code += ", &Ops" + utostr(OpsNo) + "[0], Ops" + utostr(OpsNo) +
-            ".size()";
-        } else if (NodeHasInFlag || NodeHasOptInFlag || HasImpInputs)
-          AllOps.push_back("InFlag");
-
-        unsigned NumOps = AllOps.size();
-        if (NumOps) {
-          if (!NodeHasOptInFlag && NumOps < 4) {
-            for (unsigned i = 0; i != NumOps; ++i)
-              Code += ", " + AllOps[i];
-          } else {
-            std::string OpsCode = "SDOperand Ops" + utostr(OpsNo) + "[] = { ";
-            for (unsigned i = 0; i != NumOps; ++i) {
-              OpsCode += AllOps[i];
-              if (i != NumOps-1)
-                OpsCode += ", ";
-            }
-            emitCode(OpsCode + " };");
-            Code += ", Ops" + utostr(OpsNo) + ", ";
-            if (NodeHasOptInFlag) {
-              Code += "HasInFlag ? ";
-              Code += utostr(NumOps) + " : " + utostr(NumOps-1);
-            } else
-              Code += utostr(NumOps);
+      if (NodeHasChain) {
+        if (IsVariadic)
+          emitCode("Ops" + utostr(OpsNo) + ".push_back(" + ChainName + ");");
+        else
+          AllOps.push_back(ChainName);
+      }
+
+      if (IsVariadic) {
+        if (NodeHasInFlag || HasImpInputs)
+          emitCode("Ops" + utostr(OpsNo) + ".push_back(InFlag);");
+        else if (NodeHasOptInFlag) {
+          emitCode("if (HasInFlag)");
+          emitCode("  Ops" + utostr(OpsNo) + ".push_back(InFlag);");
+        }
+        Code += ", &Ops" + utostr(OpsNo) + "[0], Ops" + utostr(OpsNo) +
+          ".size()";
+      } else if (NodeHasInFlag || NodeHasOptInFlag || HasImpInputs)
+        AllOps.push_back("InFlag");
+
+      unsigned NumOps = AllOps.size();
+      if (NumOps) {
+        if (!NodeHasOptInFlag && NumOps < 4) {
+          for (unsigned i = 0; i != NumOps; ++i)
+            Code += ", " + AllOps[i];
+        } else {
+          std::string OpsCode = "SDOperand Ops" + utostr(OpsNo) + "[] = { ";
+          for (unsigned i = 0; i != NumOps; ++i) {
+            OpsCode += AllOps[i];
+            if (i != NumOps-1)
+              OpsCode += ", ";
           }
-        }
-            
-        if (!isRoot)
-          Code += "), 0";
-        emitCode(Code2 + Code + ");");
-
-        if (NodeHasChain) {
-          // Remember which op produces the chain.
-          if (!isRoot)
-            emitCode(ChainName + " = SDOperand(" + NodeName +
-                     ".Val, " + utostr(NumResults+NumDstRegs) + ");");
-          else
-            emitCode(ChainName + " = SDOperand(" + NodeName +
-                     ", " + utostr(NumResults+NumDstRegs) + ");");
-        }
-
-        if (!isRoot) {
-          NodeOps.push_back("Tmp" + utostr(ResNo));
-          return NodeOps;
-        }
-
-        bool NeedReplace = false;
-        if (NodeHasOutFlag) {
-          if (!InFlagDecled) {
-            emitCode("SDOperand InFlag(ResNode, " + 
-                   utostr(NumResults+NumDstRegs+(unsigned)NodeHasChain) + ");");
-            InFlagDecled = true;
+          emitCode(OpsCode + " };");
+          Code += ", Ops" + utostr(OpsNo) + ", ";
+          if (NodeHasOptInFlag) {
+            Code += "HasInFlag ? ";
+            Code += utostr(NumOps) + " : " + utostr(NumOps-1);
           } else
-            emitCode("InFlag = SDOperand(ResNode, " + 
-                   utostr(NumResults+NumDstRegs+(unsigned)NodeHasChain) + ");");
+            Code += utostr(NumOps);
         }
+      }
+          
+      if (!isRoot)
+        Code += "), 0";
 
-        if (FoldedChains.size() > 0) {
-          std::string Code;
-          for (unsigned j = 0, e = FoldedChains.size(); j < e; j++)
-            emitCode("ReplaceUses(SDOperand(" +
-                     FoldedChains[j].first + ".Val, " + 
-                     utostr(FoldedChains[j].second) + "), SDOperand(ResNode, " +
-                     utostr(NumResults+NumDstRegs) + "));");
-          NeedReplace = true;
-        }
-
-        if (NodeHasOutFlag) {
-          if (FoldedFlag.first != "") {
-            emitCode("ReplaceUses(SDOperand(" + FoldedFlag.first + ".Val, " +
-                     utostr(FoldedFlag.second) + "), InFlag);");
-          } else {
-            assert(NodeHasProperty(Pattern, SDNPOutFlag, CGP));
-            emitCode("ReplaceUses(SDOperand(N.Val, " +
-                     utostr(NumPatResults + (unsigned)InputHasChain)
-                     +"), InFlag);");
-          }
-          NeedReplace = true;
-        }
+      bool NeedReplace = false;
+      if (!isRoot) {
+        NodeOps.push_back("Tmp" + utostr(ResNo));
+      } else {
 
-        if (NeedReplace && InputHasChain)
-          emitCode("ReplaceUses(SDOperand(N.Val, " + 
-                   utostr(NumPatResults) + "), SDOperand(" + ChainName
-                   + ".Val, " + ChainName + ".ResNo" + "));");
-
-        // User does not expect the instruction would produce a chain!
-        if ((!InputHasChain && NodeHasChain) && NodeHasOutFlag) {
-          ;
-        } else if (InputHasChain && !NodeHasChain) {
-          // One of the inner node produces a chain.
-          if (NodeHasOutFlag)
-            emitCode("ReplaceUses(SDOperand(N.Val, " + utostr(NumPatResults+1) +
-                     "), SDOperand(ResNode, N.ResNo-1));");
-          emitCode("ReplaceUses(SDOperand(N.Val, " + utostr(NumPatResults) +
-                   "), " + ChainName + ");");
-        }
+      if (NodeHasOutFlag) {
+        if (!InFlagDecled) {
+          After.push_back("SDOperand InFlag(ResNode, " + 
+                          utostr(NumResults+NumDstRegs+(unsigned)NodeHasChain) +
+                          ");");
+          InFlagDecled = true;
+        } else
+          After.push_back("InFlag = SDOperand(ResNode, " + 
+                          utostr(NumResults+NumDstRegs+(unsigned)NodeHasChain) +
+                          ");");
+      }
 
-        emitCode("return ResNode;");
-      } else {
-        std::string Code = "return CurDAG->SelectNodeTo(N.Val, Opc" +
-          utostr(OpcNo);
-        if (N->getTypeNum(0) != MVT::isVoid)
-          Code += ", VT" + utostr(VTNo);
-        if (NodeHasOutFlag)
-          Code += ", MVT::Flag";
+      if (FoldedChains.size() > 0) {
+        std::string Code;
+        for (unsigned j = 0, e = FoldedChains.size(); j < e; j++)
+          After.push_back("ReplaceUses(SDOperand(" +
+                          FoldedChains[j].first + ".Val, " + 
+                          utostr(FoldedChains[j].second) +
+                          "), SDOperand(ResNode, " +
+                          utostr(NumResults+NumDstRegs) + "));");
+        NeedReplace = true;
+      }
 
-        if (NodeHasInFlag || NodeHasOptInFlag || HasImpInputs)
-          AllOps.push_back("InFlag");
+      if (NodeHasOutFlag) {
+        if (FoldedFlag.first != "") {
+          After.push_back("ReplaceUses(SDOperand(" + FoldedFlag.first +
+                          ".Val, " +
+                          utostr(FoldedFlag.second) + "), InFlag);");
+        } else {
+          assert(NodeHasProperty(Pattern, SDNPOutFlag, CGP));
+          After.push_back("ReplaceUses(SDOperand(N.Val, " +
+                          utostr(NumPatResults + (unsigned)InputHasChain)
+                          +"), InFlag);");
+        }
+        NeedReplace = true;
+      }
+
+      if (NeedReplace && InputHasChain) {
+        After.push_back("ReplaceUses(SDOperand(N.Val, " + 
+                        utostr(NumPatResults) + "), SDOperand(" + ChainName
+                        + ".Val, " + ChainName + ".ResNo" + "));");
+        ChainAssignmentNeeded |= NodeHasChain;
+      }
+
+      // User does not expect the instruction would produce a chain!
+      if ((!InputHasChain && NodeHasChain) && NodeHasOutFlag) {
+        ;
+      } else if (InputHasChain && !NodeHasChain) {
+        // One of the inner node produces a chain.
+        if (NodeHasOutFlag)
+          After.push_back("ReplaceUses(SDOperand(N.Val, " +
+                          utostr(NumPatResults+1) +
+                          "), SDOperand(ResNode, N.ResNo-1));");
+        After.push_back("ReplaceUses(SDOperand(N.Val, " +
+                        utostr(NumPatResults) + "), " + ChainName + ");");
+        NeedReplace = true;
+      }
+      }
 
-        unsigned NumOps = AllOps.size();
-        if (NumOps) {
-          if (!NodeHasOptInFlag && NumOps < 4) {
-            for (unsigned i = 0; i != NumOps; ++i)
-              Code += ", " + AllOps[i];
-          } else {
-            std::string OpsCode = "SDOperand Ops" + utostr(OpcNo) + "[] = { ";
-            for (unsigned i = 0; i != NumOps; ++i) {
-              OpsCode += AllOps[i];
-              if (i != NumOps-1)
-                OpsCode += ", ";
-            }
-            emitCode(OpsCode + " };");
-            Code += ", Ops" + utostr(OpcNo) + ", ";
-            Code += utostr(NumOps);
-          }
-        }
-        emitCode(Code + ");");
-        emitOpcode(II.Namespace + "::" + II.TheDef->getName());
-        if (N->getTypeNum(0) != MVT::isVoid)
-          emitVT(getEnumName(N->getTypeNum(0)));
+      if (ChainAssignmentNeeded) {
+        // Remember which op produces the chain.
+        std::string ChainAssign;
+        if (!isRoot)
+          ChainAssign = ChainName + " = SDOperand(" + NodeName +
+                        ".Val, " + utostr(NumResults+NumDstRegs) + ");";
+        else
+          ChainAssign = ChainName + " = SDOperand(" + NodeName +
+                        ", " + utostr(NumResults+NumDstRegs) + ");";
+
+        After.push_front(ChainAssign);
+      }
+
+      // Use getTargetNode or SelectNodeTo? The safe choice is getTargetNode,
+      // but SelectNodeTo can be faster.
+      //
+      // SelectNodeTo is not safe in a non-root context, or if there is any
+      // replacement of results needed.
+      //
+      // SelectNodeTo is not profitable if it would require a dynamically
+      // allocated operand list in a situation where getTargetNode would be
+      // able to reuse a co-allocated operand list (as in a unary, binary or
+      // ternary SDNode, for example).
+      //
+      if (!isRoot || NeedReplace ||
+          (!IsVariadic && AllOps.size() < 4 &&
+           Pattern->getNumChildren() + InputHasChain + NodeHasInFlag <
+             AllOps.size())) {
+        Code = "CurDAG->getTargetNode(" + Code;
+      } else {
+        Code = "CurDAG->SelectNodeTo(N.Val, " + Code;
       }
+      if (isRoot) {
+        if (After.empty())
+          CodePrefix = "return ";
+        else
+          After.push_back("return ResNode;");
+      }
+
+      emitCode(CodePrefix + Code + ");");
+      for (unsigned i = 0, e = After.size(); i != e; ++i)
+        emitCode(After[i]);
 
       return NodeOps;
     } else if (Op->isSubClassOf("SDNodeXForm")) {





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